1. Field of the Invention
The present invention relates to an illumination apparatus.
2. Description of the Related Art
Small size light sources that use an excitation light source and a fluorescent member in combination have been newly developed nowadays. In some of such light sources, a plurality of types of fluorescent members are used to create illumination light by mixing light emitted from the plurality of fluorescent members. For example, Patent Document 1 discloses, as shown in FIGS. 20 and 21, an illumination apparatus 910 as such that includes a light source 911 that emits excitation light and a plurality of fluorescent members 913, 914, 915, wherein the plurality of fluorescent members are arranged along a direction perpendicular to the direction of optical path of the excitation light. This illumination apparatus is intended to allow easy setting of color balance of a white light source and to improve the light conversion efficiency. FIG. 20 is a side view illustrating the construction of the illumination apparatus described in Patent Document 1. FIG. 21 is a plan view of the illumination apparatus shown in FIG. 20.
In conventional illumination apparatuses, if a plurality of fluorescent members are used in combination, light emitted from one fluorescent member is absorbed again by another fluorescent member, and the light conversion efficiency cannot be enhanced. In contrast, in the illumination apparatus described in Patent Document 1, since a plurality of fluorescent members are arranged along a direction perpendicular to the direction of the optical path of the excitation light, re-absorption in the optical path direction hardly occurs.
In the following description, the emission axis in which excitation light is emitted from the center point of the excitation light emitting area of a light source at the highest intensity will be referred to as the optical axis.